1. Field of the Invention
The present invention relates to a maintenance system for subscriber management data in a packet switched network to be used when subscriber terminal management data on a packet switching exchange are to be updated following new registrations of subscriber terminals, change of attributes, or cancellation of registrations of subscriber terminals in a packet switched network.
2. Description of the Prior Art
FIG. 1 is a block diagram showing a conventional maintenance system for subscriber terminal management data in a packet switched network. In the figure, 1a and 1b are packet switching exchanges which constitute a packet switched network; 2a and 2b are subscriber terminals incorporated in each of the packet switching exchanges 1a and 1b; 3 is a terminal line for connecting the subscriber terminals 2a and 2b to the packet switching exchanges 1a and 1b respectively; 4a and 4b are maintenance consoles connected to each of the packet switching exchanges 1a and 1b.
FIG. 3 is a block diagram showing a table configuration of subscriber information in each packet switching exchange 1a (1b). Each packet switching exchange 1a (1b) is provided with a line information table 11 which stores circuit I/F (interface) information of the equipment such as line speed or electric I/F conditions indexed by terminal line 3, and a terminal information table 12 which stores information such as the attributes of the incorporated subscriber terminal 2a (2b), or the attributes of communication services according to CCITT recommendation X. 25. When a PVC (permanent virtual circuit) service is performed there is provided a PVC information table 13 which stores connection information between each of the PVC logical channels and the subscriber terminals at the other end of a line. In that case, the same connection information is stored in the PVC information table 13 of each packet switching exchange in which subscriber terminals at the other end of the line are incorporated.
Operation will be explained in the following. In a packet switched network as mentioned in the above, when either a new subscriber terminal 2a (2b) is to be registered, an attribute of a communication service according to CCITT recommendation X. 25 of a subscriber terminal 2a (2b) is to be changed or an existing subscriber terminal 2a (2b) registration is to be cancelled, maintenance has to be performed for updating such information. On the subscriber terminal 2a of the packet switching exchange 1a, when a new registration, a change of attribute or registration cancellation is to be performed, the line information table 11 or the terminal information table 12 in a memory is changed by inputting data from the maintenance console 4a connected to the packet switching exchange 1a. When there is a change in the attributes of the PVC communication service (setting of PVC/deleting of PVC) between the subscriber terminal 2b incorporated in the packet switching exchange 1b and the subscriber terminal 2a, not only the PVC information table 13 in the packet switching exchange 1a but also the PVC information table 13 in the packet switching exchange 1b must be changed by the operation of the maintenance console 4b connected to the packet switching exchange 1b.
FIG. 2 is a block diagram showing another conventional maintenance system for subscriber terminal management data in a packet switched network. In the figure, 1a and 1b are packet switching exchanges, 2a and 2b are subscriber terminals and 3 is a terminal line. These are equivalent to those shown in FIG. 1. A component part 5 is a network control processor (hereinafter referred to as NCP) which manages the whole packet switched network, provided in a packet switched network which is formed by the packet switching exchanges 1a and 1b. Such an NCP is shown in Japanese patent application of laid-open No. 234158/86, and it is connected to the packet switched network through a trunk line as one of its nodes. A component part 6, connected to the NCP 5, is a subscriber information data base file in which the subscriber terminal management data for each of the packet switching exchanges 1a and 1b are stored, and these data are unitarily managed by the NCP 5, and 7 is an operator console into which subscriber data and the like are inputted and is connected to the NCP 5.
Operation will be explained in the following. In the case where new registrations, changes of attributes, or cancellation of registrations regarding the subscriber terminal 2a are to be performed for the packet switching exchange 1a, at first subscriber data are inputted from the operator console 7 to the NCP 5 to change the line information and the terminal information of the subscriber terminal 2a on the file 6 of the subscriber information data base. After that the updated line information and terminal information are transferred from the NCP 5 to the packet switching exchange 1a. In the packet switching exchange 1a, each of the transferred pieces of information is overwritten on an old one in the line information table 11 and the terminal information table 12. Similarly, if there is any change in an attribute of the PVC communication service between the subscriber terminal 2a and the subscriber terminal 2b in the packet switching exchange 1b, subscriber data are inputted from the operator console 7 to the NCP 5 to change the information concerning the attribute of the relevant PVC communication service on the file 6 of the subscriber information data base. After that, each of the updated attribute information data of the PVC communication service are transferred from the NCP 5 to the switching exchanges 1a and 1b. At each of the packet switching exchanges 1a and 1b, the transferred information is overwritten on the old information is the respective PVC information tables 13. Usually, the changes of the data in tables 11, 12 and 13 are performed when a certain number of changes as to the subscriber terminals are collected, or periodically (for example, once a month).
As the conventional maintenance system of operation management data in a packet switched network is constituted and managed as mentioned above, in the example shown in FIG. 1, changing information in a plurality of tables such as the line information table 11 has to be done for each of the packet switching exchanges 1a and 1b at site; this is not only troublesome for unitary management of data but also there is a problem, as seen in the example of the PVC information table 13, that when the information updated ranges over a plurality of packet switching exchanges 1a and 1b, the updating in each of these switching exchanges requires synchronization with each other. As in the case shown in FIG. 2, even when a network control processor 5 is provided in a packet switched network for a unitary management of a data base and updated line information, terminal information and PVC information are transferred from the processor to the packet switching exchanges 1a and 1b, and in order to make effective each of the tables in which updated data transferred to the packet switching exchanges are overwritten, re-starting of a system in each of the packet switching exchanges 1a and 1b is needed; therefore it has been a problem at that time that the communication services for the subscriber terminals 2a and 2b are cut off, despite the face that they have no relation to the information change being processed in the packet switching exchanges 1a and 1b.